The present invention relates to a thin-film electroluminescent display panel (referred to as "EL display panel" hereinafter) and, more particularly, to dielectric layers suitable for the EL display panel.
Recently, an Si.sub.3 N.sub.4 film known as an amorphous thin film has been adapted for a dielectric layer for the EL display panel because of high resistivity to moisture invading and high resistance to an applied voltage.
However, the Si.sub.3 N.sub.4 film has the disadvantage that the adhesion strength to the other layers of the EL display panel is weak and an interface level tends to be generated. The weak adherence strength may lead to detaching the Si.sub.3 N.sub.4 film from the other layers. The interface level causes an electroluminescence emission starting voltage to become irregular over an emission surface of an electroluminescence layer.
To reduce the effect by the above defects, the surface of a substrate on which the Si.sub.3 N.sub.4 film is formed must be very clean and smooth. However, such requirement is disadvantageous for mass production with factory equipment that is not expensive.